Prior to the present invention, there has existed a plurality of problems and difficulties with box tools of the type to which this invention is directed, such as the type dealt with in the Plevyak U.S. Pat. No. 3,538,731, the disclosure of which is incorporated herein by reference. Prior to the present invention a major undesirable inherent problem associated with all prior box tools of these type was the fact that upon the separation of the workpiece from the cutting blade and supporting rollers subsequent to the cutting operation, the rotating workpiece became scarred in a corkscrew manner because of the residual pressure of the cutting blade and support rollers on the cut surface of the workpiece. Another problem also arose from the fact that when a tool post carrying a cutting knife adapted to operate on a workpiece supported on a spindle chuck and the knife thereof cutting from a second position as compared to the cutting piece of the box tool blade to which this invention is directed, eventual dulling of the side position blade required the removal of that blade and reinsertion thereof and a resulting resetting after the sharpening, which resetting also required that the blade of the box tool to which this invention is directed be also reset again because of the fact that the separate blades are commonly actuated by a single lever mechanism, whereby adjustment of one blade requires the resetting of the other blade prior to the present invention.